Cars and homes are submerged in flood waters in High River, Alberta on Thursday. / Jeff McIntosh, AP

by Staff and wire reports, USA TODAY

by Staff and wire reports, USA TODAY

Flooding in western Canada on Friday left at least two people dead and forced the evacuation of downtown Calgary and several towns in southern Alberta,after days of rain and melting mountain snow inundated major rivers.

The two victims are two men whose bodies were spotted floating in the Highwood River near High River on Thursday.

Canadian Prime Minister Stephen Harper toured the affected area and said officials do not know if the flooding will worsen.

"I don't think any of us have seen anything like this before," Harper said. "The magnitude is just extraordinary."

Although 230,000 people typically work in the city's core on Fridays, officials said the majority did not show up, CTV reported.

The city's iconic sports area, the Saddledome, which is to host the annual Calgary Stampede in two weeks, had water up to the 10th row, as the Bow River continued to rise.

"The good news is that it is slowly reducing. We have peaked, and we are seeing a slow decrease," he said, adding the fiver could rise again because of a surge in flow.

More than two dozen Calgary neighborhoods were evacuated, and several were submerged. Authorities predicted that up to 100,000 people might be forced out of their homes in the city of 1 million residents, which hosted the 1988 Winter Olympics.

Officials said the evacuation would take place in stages over the next few days.

As of Friday afternoon, about 1,500 residents were in emergency shelters, the mayor said, with the majority of others staying with relatives or friends.

The city zoo was under several feet of water, and animals were moved to higher ground or relocated.

A state of emergency was declared in a large area south of Calgary after floodwaters washed out bridges and roads in 12 towns. The Trans-Canada Highway was closed, and the mountain resort towns of Banff and Canmore were isolated.

Motorists who were trapped overnight Wednesday by water spilling over Canada's main western highway had to be rescued by helicopter, Town of Canmore spokeswoman Sally Caudill said.

"I woke up at about 3 o'clock in morning to the sound of this kind of rumbling, and it was the creek," said Wade Graham, a resident of Canmore. "At first it was just intense, pretty powerful, amazing thing to watch. As daylight came, it just got bigger and bigger and wider and wider, and it's still getting bigger and bigger and wider and wider."

Bruce Burrell, director of the Calgary Emergency Management Agency, said water levels on the Bow River aren't expected to subside until Saturday afternoon. The Bow River Basin already has been battered with up to 100 mm (3.9 inches) of rain.

"Depending on the extent of flooding we experience overnight, there may be areas of the city where people are not going to be able to get into until the weekend," he told a news conference.

In High River, Mounties asked people with motorboats to help rescue at least a dozen stranded homeowners.

"We have people on their rooftops who were unable to evacuate fast enough," said RCMP Sgt. Patricia Neely.

Environment Canada issued a rainfall warning for the affected areas, estimating as much as 100 millimeters more rain could fall in the next two days.